It turns out that just blindly enabling read prefetch is wrong for the
older (and buggy) oz6833 bridge.  fixed in the attached patch.

- don't touch the oz6832/6833
- more verbose
- only set the read prefetch and the write burst bits

it broke on some old laptop with a cardbus tulip.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>